A tool of steel, generally tapering, and of a polygonal form, with from four to eight cutting edges, for smoothing or enlarging holes in metal; sometimes made smooth or without edges, as for burnishing pivot holes in watches; a reamer. The broach for gun barrels is commonly square and without taper.

(b)

A straight tool with file teeth, made of steel, to be pressed through irregular holes in metal that cannot be dressed by revolving tools; a drift.